Biocidal compositions containing copper compounds

ABSTRACT

The present invention relates to certain processes and compositions useful for inhibiting and/or controlling the growth of slime in water and, in particular, water employed for industrial purposes. Water employed in the manufacture of pulp paper and water employed in cooling water systems, as well as other industrial waters, provide environments which are conducive to slime formations. The novel compositions of the present invention are mixtures which show unexpected synergistic activity against microorganisms, including bacteria, fungi and algae, which produce slime in aqueous systems. The slime, of course, is objectionable from an operational and/or an aesthetic point of view. Specifically, the invention is directed to and the use of a composition comprising a combination of 5-chloro-4-phenyl-1,2dithiole-3-one or derivatives thereof and copper sulfate (CuSO4). The inventive compositions inhibit the growth of slime in water, or more specifically, possess biocidal activity against bacteria, fungi and/or algae. The derivatives contemplated for use in accordance with the present invention are those which possess the capacity to kill or inhibit the growth of slime-forming microorganisms such as bacteria, fungi and algae.

United States Patent [191 Brink, Jr. et a1.

[ June 28,1974

[75] Inventors: Robert H. Brink, Jr., Doylestown; Bernard F. Shema, Glenside; Paul Swered, Philadelphia, all of Pa.

[73] Assignee: Betz Laboratories, Inc., Trevose, Pa. [22] Filed: Jan. 24, 1972 {21 Appl. No.: 220,361

[52] US. Cl 424/141, 71/67, 162/190, 424/277' [51] Int. Cl A0ln 13/00 [58] Field of Search 71/67; 424/277, 141; 162/190 [56] References Cited UNITED STATES PATENTS 2,400,677 5/1946 Allen 71/67 3,031,372 4/1962 Brack 424/277 3,634,061 1/1972 Geiger 71/67 Primary Examiner-James 0. Thomas, Jr.

F. Miller [5 7] ABSTRACT The present invention relates to certain processes and compositions useful for inhibiting and/or controlling the growth of slime in water and, in particular, water employed for industrial purposes. Water employed in the manufacture of pulp paper and water employed in cooling water systems, as well as other industrial waters, provide environments which are conducive to slime formations. The novel compositions of the present invention are mixtures which show unexpected synergistic activity against microorganisms, including bacteria, fungi and algae, which produce slime in aqueous systems. The slime, of course, is objectionable from an operational and/or an aesthetic point of view. Specifically, the invention is directed to and the use of a composition comprising a combination of 5- chloro-4-phenyl-l,2-dithiole-3-one or derivatives thereof and copper sulfate (CuSO The inventive compositions inhibit the growth of slime in water, or

more specifically, possess bioci-dal activity against bacteria, fungi and/or algae. The derivatives contemplated for use in accordance with the present invention are those which possess the capacity to kill or inhibit the growth of slime-forming microorganisms such as bacteria, fungi and algae.

10 Claims, N0 Drawings BIOCIDAL COMPOSITIONS CONTAINING COPPER COMPOUNDS BACKGROUND OF THE INVENTION The formation of slime by microorganisms is a problem which attends many systems. For example, lagoons, lakes, ponds, pools and such systems as cooling water systems and pulp and paper mill systems all possess conditions which are conducive to the growth and reproduction of slime-forming microorganisms. In both once-through and recirculating cooling systems, for example, which employ large quantities of water as a cooling medium, the formation of slime by microorganisms is an extensive and constant problem.

Airborne organisms are readily entrained in the water from cooling towers and find this warm medium an ideal environment for growth and multiplication. Aerobic and heliotropic organisms flourish on the tower proper while other organisms colonize and grow in such areas as the tower sump and the piping and passages of the cooling system. Such slime serves to deteriorate the tower structure in the case of wooden towers. In addition, the deposition of slime on metal surfaces promotes corrosion. Furthermore, slime carried through the cooling system plugs and fouls lines, valves, strainers, etc. and deposits on heat exchange surfaces. In the latter case, the impedance of heat transfer can greatly reduce the efficiency of the cooling system.

In pulp and paper mill systems, slime formed by microorganisms is also frequently and, in fact, commonly encountered. Fouling or plugging by slime also occurs in the case of pulp and paper mill systems. Of greater significance, the slime becomes entrained in the paper produced to cause breakouts on the paper machines with consequent work stoppages and the loss of production time or unsightly blemishes in the final product; this, of course, results in rejects and wasted output. The previously discussed problems have resulted in the extensive utilization of biocides in cooling water and pulp and paper mill systems. Materials which have enjoyed widespread use in such applications include chlorine, organo-mercurials, chlorinated phenols, organobromines, and various organo-sulfur compounds. All of these componds are generally useful for this purpose but each is attended by a variety of impediments. For example, chlorination is limited both by its specific toxicity for slime-forming organisms at economic levels and by the ability of chlorine to react which results in the expenditure of the chlorine before its full biocidal function may be achieved. Other biocides are attended by high costs, odor problems and hazards in respect to storage, use or handling which limit their utility. To date, no one compound or type of compound has achieved a clearly established predominance in respect to the applications discussed. Likewise, lagoons, ponds, lakes and even pools, either used for pleasure purposes or used for industrial purposes for the disposal and storage of industrial wastes become, during the warm weather, besieged by slime due to microorganism growth and reproduction. In the case of the recreational areas, the problem of infection, odor, etc. is obvious. In the case of industrial storage or disposal of in dustrial materials, the microorganisms cause additional problems which must be eliminated prior to the materials use or the waste is treated for disposal.

It is the object of the present invention to provide compositions for controlling slime-forming microor ganisms in aqueous systems, such as cooling water systems and pulp and paper mill systems, and for controlling slime formation or microorganism populations in aqueous bodiesin general. Moreover, another object of the invention is the provision of methods for preserving materials and for controlling slime-forming microorganisms in any aqueous system which is conducive to the growth and reproduction of microorganisms and, in particular, cooling water and paper and pulp mill systems. These methods employ a combination of 5- chloro-4-phenyl-l,2-dithiole-3-one or derivatives thereof and copper sulfate (CuSO,).

In the practice of the invention, the combination is added to the particular material to be preserved or to the system being treated, for example, cooling water systems, paper and pulp mill systems, pools, ponds, lagoons, lakes, etc., in a quantity adequate to control the slime-forming microorganisms which are contained by,

orwhich may become entrained in, the system which,

is treated. It has been found that such compositions and methods control the growth and occurrence of such microorganisms as may populate these particular systems.

7, GENERAL DESCRIPTION OF THE INVENTION As earlier stated, the inventive compositions comprise a combination-of 5-chloro-4-phenyl-l,Zdithiole- 3-one or derivatives thereof and copper sulfate (CuSO either compound being present in such quantity as to impart a synergistic behavior for the purpose to the composition as a whole. Preferably, the compositions contain a percentage by weight ranging from about 5 to about percent of the dithiole-3-one compound and from about 5 to about 95 percent of the copper sulfate. When these two ingredients are mixed either beforehand or by addition to the aqueous system individually, the resulting mixtures possess a high degree of slimicidal activity which could not have been predicted beforehand from the known activity of the individual ingredients comprising the mixture. Accordingly, it is therefore possible to produce a more effective slime-control agent than has previous been available. Because of the enhanced activity of the mixture, the total quantity of biocide required for an effective treatment may be reduced. In addition, the high degree of biocidal effectiveness which is provided by each of the ingredients may be exploited without use of the higher concentrations of each. This feature is not only important and advantageous from an economical point of view, but also most desirable from the pollution or ecological standpoints. In this regard, it might be pointed out that the smaller the amount of a chemical that is required for effective treatment, the smaller the problem in treating the wastes from these systems. In both cooling water systems and in paper and pulp mill systems, certain discharge of waste water, e.g., blowdown in cooling water systems, is a necessity. However, because of the current concern and legislation regarding the discharge of wastes, the effluent waste water must be treated to reduce and, hopefully. to eliminate any undesirable constituents. This treatment, of course, is time-consuming and costly. Accordingly, a reduction in additive usage will result in a corresponding reduction in costs for the treatment of wastes containing these additives.

In order to illustrate this synergistic activity, the efficacy and the comparative effectiveness of the inventive compositions, various tests were utilized and will be described following.

SPECIFIC EMBODIMENTS EXAMPLE 1 and copper sulfate (referred to as Compound B in thisexample and in the Test Equations and in Tables 1 through 1C) in the weight ratios expressed in the Tables which follow. The compositions were tested for synergistic activity in accordance with the method described. The synergism test was utilized to evaluate each of the combinations of this example.

Synergistic Index Test Synergistic activity was demonstrated by adding Compound A and Compound B in varying ratios and over a range of concentrations to liquid nutrient medium which was subsequently inoculated with a standard volume of suspension of the bacterium Aerobacter aerogenes. Following two days incubation, the lowest concentration of each ratio which prevented growth of the bacteria was taken as the end point. Growth or nogrowth was determined by turbidity or clarity, respectively, in the medium. End points for the various mixtures were then compared with end points for the pure active ingredients working alone in concomitantly prepared culture bottles. Synergism was determined by the method described by Kull et al. [F. C. Kull, P. C. Eisman, H. D. Sylwestrowicz and R. L. Mayer, Applied Microbiology, 9, 53841 (1961 and the relationships,

Q,,/Q,, Q /Q l is additivity 1 is antagonism l is synergism where,

Qa Quantity of Compound A acting alone, producing an end point Qb Quantity of Compound B acting alone, producing an end point QA Quantity of Compound A, in the mixture, producing an end point QB Quantity of Compound B, in the mixture, producing an end point For mixtures of Compounds A and B, and for Compound A and Compound, B acting alone, the following results were observed: 1

- 4 the ingredients are compatible over the wide percentage by weight range.

BACTERICIDAL EFFECTIVENESS The bactericidal effectiveness of the mixture of Compound A and Compound B of this example is demonstrated by the following Table in which the inhibiting power of a /50 by weight mixture of A and B is shown. Aerobacter aerogenes was employed as the test organism and a substrate technique was utilized. Specifically, the biocidal mixture was added in gradually increasing quantities to nutrient agar media which was then inoculated with A. aerogenes. The preparation was then incubated for 48 hours. The values set forth in the Table indicate the quantity of biocide required, in parts by weight for each one million parts by weight of the medium, in order to achieve complete inhibition of the growth of the test organism.

TABLE 1A Quantity (ppm) required for inhibition Compound A (5%), Compound B (571), Inert (90%) F UNGICIDAL EFFECTIVENESS In order to test the effectiveness of the inventive mixtures in respect to fungi, evaluations were made following the procedures described by B. F. Shema and J. H. Conkey [.Iournal for the Technical Association of The Pulp and Paper Industry, 36, 20A-3OA, 1953)]. The described procedure generally entails incorporating the biocide under test in a nutrient substrate such as agar, malt, etc. and pouring the resulting medium into a Petri dish and allowing the medium to solidify. A button of fungus inoculum is placed on the surface of the solidified medium and the medium is incubated for a period of 14 days. After the period, the diameter. of the colony is measured and compared with the diameter of the button of inoculum originally placed upon the surface. If there is no increase in the diameter, the growth of the fungus is considered to be completely inhibited and the treatment level which accomplished this is considered the inhibitory concentration. The fungal species utilized as the test microorganism to evaluate the efficacy of the present mixture were Penicillium expansum and Aspergillus niger.

TABLE 1 Weight Ratio Quantities Producing End Points (pDm) OA QB QA QB of A to B QA QB Mixture 021 Oh Qa Qb where just minor amounts of one or the other are present. This discovery of synergism at the lower levels is extremely valuable since it illustrates conclusivelythat TABLE 1B Quantity (ppm) for inhibition Biocidal Material P. expansum A. niger Compound A (5%), 9 9 Compound B (5%), lnen synergistic biocidal product comprises from about 5 to 10 percent by weight of the copper sulfate, about 5 to 10 percent by weight of the 5-chloro-4-phenyl-l,2- dithiole-3-one and the remainder composed of such materials as surfactants, stabilizers, organic solvents,

such as lower alcohols, aromatic hydrocarbons and/or water.

Surfactants such as the alkylaryl polyether alcohols, polyether alcohols, sulfonates and sulfates, and the 10 like, may be employed to enhance the dispersibility and denced their ability to form slime in actual industrial systems.

In the testing of recirculating water samples, a sub strate evaluation was employed. In such testing, identical portions of water samples are treated with varying concentrations of biocide and two portions are left untreated to serve as controls. The control portions are plated for total count at the beginning of biocide treatment and all portions are plated for total count at some suitable time period(s) after beginning biocide treat ment. Using the counts obtained from the plating, the percentage kill (based on the initial control count) may be calculated. In this evaluation, the water sample was taken from a Nash vacuum system from a paper mill located in the northeastern United States.

For the purposes of comparison, the mixture of A and B was evaluated together with two recognized commercial biocides, Pentachlorophenol and a Coms l P EIQGE TABLE 1c stability of these dispersions. The foregoing solutions of the biocidal compositions are utilized in order to insure the rapid and uniform dispersibility of the biocides within the industrial water which is treated. It has been found that either aqueous or non-aqueous solvents are generally suitable in the preparation of compositions of the invention, e.g., methyl cellosolve, organic solvents such as the aliphatic and aromatic hydrocarbons, e.g., kerosene. Based upon the synergism study as outlined above, it was ascertained that in the treatment of paper mill and cooling water, effectivebiocidal action is obtained when the concentration or treatment level of the combination or admixture of biocides is between 0.1 parts per million to 1,000 parts per million, and preferably between one and l00 parts per million, based upon the total content of the aqueous system treated, such as the total quantity of cooling water or paper mill water The compositions may also be utilized for the preservation of slurries and emulsions containing carbohyd a es. Pi tai s, fats. O l 939- .dq a evels. f t s Biocidal Material Compound A (5%), Compound B (5%), Inert (90%) do. do. do.

do. do. do.

do. do. do.

do. do. do. Pentachlorophenol (100%) do. Commercial Product active: Combination of dithiocarbamates) do. do. do.

do. do. do.

do. do. do.

do. do. do.

Quantity of Percent kill biocide (ppm) after 3 hours 5 44 I0 80 25 94 I00 I00 I00 5 0 IO 34 25 53 50 70 I00 7 5 l3 l0 I9 25 2| 50 32 lOO 39 pollution abatement, waste treatment costs and the preservation of the ecological strain.

When the inventive compositions are employed in the treatment of cooling or paper mill water, they are preferably utilized in the form of relatively dilute solutions or dispersions. For example, a preferred solution comprises between 5 to 65 percent by weight of the synergistic combination in admixture with various solvents and solubilizing agents. An example of such a purpose range in the vicinity of 0.01 to 5 percent. The compositions of the invention which can be prepared by merely combining the respective ingredients and mixing thoroughly at standard conditions may be fed continuously to the treated system, e.g., by means of a metered pump, or may be fed periodically at predetermined intervals calculated to control the growth of slime-forming organisms in the system. Naturally, in the treatment of cooling water, the feeding of the inventive compositions must be designed to compensate for blowdown in those systems which employ that expedient.

Although the foregoing has been specifically directed to liquid fonnulations, the combinations of the invention may, of course, be formulated dry with well-known pelletizing agents, e.g., sodium chloride, talc, aluminate, etc. to produce solid pellets or briquettes which are added directly to the systems to be treatedThepellets or briquettes, of course, dissolve in accordance with predetermined conditions or rates.

In describing the inventive subject matter, the expression composition has been utilized. However, it is to be understood that physical compositions or combinations are not the sole utilty of the invention. If, for example, the separate ingredients of the composition" are added independently to a particular system, it is intended that this usage of the subject matter is within the scope of the invention and is to be construed within the broad interpretation of composition and/or combination.

As would be expected, the inventive composition may be added to the cooling water or paper and pulp mill systems at any convenient point. Naturally, in oncethrough or non-circulating systems, the composition must be added upstream from the point or points at which microorganism control is desired. ln circulating systems or pulp and paper systems, the compositions must be added at any point provided that the time lapse and the conditions experienced between point of addition and the point at which the effect of the composition is to be experienced are not so drastic as to result in the neutralization of the effect of the composition.

Although the invention has been described specifically as being directed to specific compositions com prising -chloro-4-phenyl-1,2-dithiole-3-one in combination with the copper sulfate, it is obvious that homologs, analogs, etc. of the dithiole-3-one compound certainly are operable for the purpose. Likewise, the derivatives of the specially exemplified copper compound, eg nitrates, chlorides, etc., also have utility in the present inventive concept. The provision, of course, is that the derivatives possess biocidal or growth inhibitory capacities with respect to bacteria, fungi, and algae.

It should be noted that while the evidence has been derived from the treatment of samples taken from a paper and pulp mill aqueous system, the compositions and methods of the present invention are broadly applicable to the treatment of aesthetic waters as well as industrial waters, such as cooling waters which are plagued by deposits formed by slime-forming organisms, or by the very presence of such organisms.

Having thus described the invention, what we claim l. A method for controlling the growth of the microorganism Aerobacter aerogenes in an aqueous system containing an amount of said microorganism which comprises adding to said system so as to contact said microorganisms an effective amount of a combination 8 comprising 5-chloro-4-phenyl-l,2-dithiole-3-one and copper sulfate (CuSO and mixtures thereof, wherein the weight ratio of the dithiole to the sulfate is from about 5 to percent to about 95 to 5 percent.

2. A method according to claim 1 wherein the combination contains approximately 50 percent by weight of each of said dithiole-3-one and said copper sulfate.

3. A method according to claim 1 wherein the combination is added to said system in any amount of from about 0.1 to about 1,000 parts by weight of said composition per parts by weight of said aqueous system.

4. A method according to claim 3 wherein the composition is added to said system in an amount of one to parts per million parts of said aqueous system.

' 5. A method according to claim 3 wherein the aqueous system is the aqueous system of a cooling water system.

6. A method according to claim 3 wherein the system is the aqueous system of a pulp and paper mill system.

7. A method of preserving materials which are subject to attack by the microorganism Aerobacter aerogenes which comprises incorporating in said material containing an amount of said microorganism from about 0.01 .to 5 percent by weight of a combination comprising 5-chloro-4-phenyl-l,2-dithiole-3-one and copper sulfate and mixtures thereof, wherein the weight ratio of the dithiole to the sulfate is from about 5 to 95 percent to about 95 to 5 percent.

8. A composition for controlling the-growth of the microorganism Aerobacter aerogenes in an aqueous system containing an amount of said microorganism comprising 5-chloro-4-phenyl, l,2-dithiole-3-one and copper sulfate, wherein the weight ratio of the dithiole to the sulfate is from about 5 to 95 percent to about 95 to 5 percent.

9. A composition according to claim 8 wherein the composition contains approximately 50 percent by weight of each of said dithiole-3-one and said copper sulfate.

10. A composition for controlling the growth of the microorganism Aerobacter aerogenes in an aqueous system containing an amount of said microorganism comprising from about 5 to 10 percent by weight of 5- chloro-4-phenyl, 1,2-dithiole-3-one and from about 5 to 10 percent by weight of copper sulfate, and the remainder composed of a material selected from the group consisting of surfactants, stabilizers, organic and inorganic solvents and mixtures thereof.

* l i =l 

2. A method according to claim 1 wherein the combination contains approximately 50 percent by weight of each of said dithiole-3-one and said copper sulfate.
 3. A method according to claim 1 wherein the combination is added to said system in any amount of from about 0.1 to about 1, 000 parts by weight of said composition per parts by weight of said aqueous system.
 4. A method according to claim 3 wherein the composition is added to said system in an amount of one to 100 parts per million parts of said aqueous system.
 5. A method according to claim 3 wherein the aqueous system is the aqueous system of a cooling water system.
 6. A method according to claim 3 wherein the system is the aqueous system of a pulp and paper mill system.
 7. A method of preserving materials which are subject to attack by the microorganism Aerobacter aerogenes which comprises incorporating in said material containing an amount of said microorganism from about 0.01 to 5 percent by weight of a combination comprising 5-chloro-4-phenyl-1,2-dithiole-3-one and copper sulfate and mixtures thereof, wherein the weight ratio of the dithiole to the sulfate is from about 5 to 95 percent to about 95 to 5 percent.
 8. A composition for controlling the growth of the microorganism Aerobacter aerogenes in an aqueous system containing an amount of said microorganism comprising 5-chloro-4-phenyl, 1,2-dithiole-3-one and copper sulfate, wherein the weight ratio of the dithiole to the sulfate is from about 5 to 95 percent to about 95 to 5 percent.
 9. A composition according to claim 8 wherein the composition contains approximately 50 percent by weight of each of said dithiole-3-one and said copper sulfate.
 10. A composition for controlling the growth of the microorganism Aerobacter aerogenes in an aqueous system containing an amount of said microorganism comprising from about 5 to 10 percent by weight of 5-chloro-4-phenyl, 1,2-dithiole-3-one and from about 5 to 10 percent by weight of copper sulfate, and the remainder composed of a material selected from the group consisting of surfactants, stabilizers, organic and inorganic solvents and mixtures thereof. 